Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755371AbaBUUoS (ORCPT ); Fri, 21 Feb 2014 15:44:18 -0500 Received: from relay3-d.mail.gandi.net ([217.70.183.195]:39893 "EHLO relay3-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755230AbaBUUoQ (ORCPT ); Fri, 21 Feb 2014 15:44:16 -0500 X-Originating-IP: 173.246.103.110 Date: Fri, 21 Feb 2014 12:44:01 -0800 From: Josh Triplett To: Andrew Morton Cc: Alexander Viro , "Paul E. McKenney" , Frederic Weisbecker , Paul Gortmaker , Mike Frysinger , Kyungsik Lee , Jiri Slaby , Eric Paris , Dwight Engen , Dave Hansen , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fs, kernel: Support disabling the uselib syscall Message-ID: <20140221204144.GA3861@jtriplet-mobl1> References: <20140221181103.GA5773@jtriplet-mobl1> <20140221121627.19e5d04dbba25984d4be8a15@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140221121627.19e5d04dbba25984d4be8a15@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 21, 2014 at 12:16:27PM -0800, Andrew Morton wrote: > On Fri, 21 Feb 2014 10:11:06 -0800 Josh Triplett wrote: > > uselib hasn't been used since libc5; glibc does not use it. Support > > turning it off. > > > > When disabled, also omit the load_elf_library implementation from > > binfmt_elf.c, which only uselib invokes. > > > > bloat-o-meter: > > add/remove: 0/4 grow/shrink: 0/1 up/down: 0/-785 (-785) > > function old new delta > > padzero 39 36 -3 > > uselib_flags 20 - -20 > > sys_uselib 168 - -168 > > SyS_uselib 168 - -168 > > load_elf_library 426 - -426 > > > > The patch disables CONFIG_USELIB by default. This important decision > should be mentioned and justified in the changelog, please. Gah, that was not intentional. Will fix in v2. I did very intentionally not make it require CONFIG_EXPERT or CONFIG_EMBEDDED, since (like CONFIG_BINFMT_AOUT) almost everyone will want it disabled, but I had intended to make it "default y". > > +#ifdef CONFIG_USELIB > > I wonder if CONFIG_SYS_USELIB would be a better identifier. We haven't > done anything consistent here. As far as I can tell, there's no use of CONFIG_SYS_* or any other consistent prefix for configuring out syscalls; all such symbols appear unprefixed. I think it would make sense to have a single common menu and prefix for configuring out unused syscalls, but given the large number of existing Kconfig options for that, I think that change ought to occur as a separate patch series that isn't also trying to add a new such option. Perhaps Dave Hansen (CCed) might be interested in incorporating such a change into his ongoing kconfig consolidation and reorganization? - Josh Triplett -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/